Note 217 — Chapter XV · Watt again visits Cornwall—Invention of the Rotary Motion—The Patent Right again assailed.

Boulton to Watt, 28th June, 1781. On the 3rd July following he writes,—“The great rotative engine is finished, and I expected the union between it and the little engine would have been performed this evening, but it can’t be till to-morrow. Robert set the elliptic out so true that it had no shake and required no alteration. It goes so much better than the little model made by Joseph that I am now ashamed to send the little one. The great model makes a delightful horizontal foot-lathe. I gave it a few strokes with my foot, and it made 30 revolutions after I withdrew it, and that in a quiet and peaceable manner, which shows how steady and frictionless it is.”